Dispenser for medicaments and method and apparatus for making same

ABSTRACT

A dispenser assembly for liquid products comprising an elongated, generally cylindrical barrel of a predetermined internal cross-sectional diameter having a discharge opening at one end and open at its opposite end, an elongated, generally cylindrical hollow plunger having an outer diameter less than the barrel internal diameter and a circumferentially extending axially directed sealing lip adjacent the tip portion having an outer diameter greater than the internal diameter of the barrel in the relaxed state to thereby flex the lip inwardly against its bias and providing the sole sliding contact between the plunger and barrel when the plunger and barrel are actuated axially relative to one another.

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/370,203 filed Apr. 5, 2002.

FIELD OF THE INVENTION

[0002] The present invention relates to a dispenser assemblies fordispensing liquid products and in particular to dispensers of the typeuseful in administering medicaments, such as liquid aspirin to childrenand to a method and apparatus for making a plunger part of thedispenser.

BACKGROUND OF THE INVENTION

[0003] The prior art as exemplified by the patents listed below showsyringe assemblies for dispensing injectable medicaments which generallycomprise an elongated, hollow barrel having luer-type fitting at thedischarge end to mount a needle or cannula and a plunger rod whichmounts a plunger usually made of rubber has radially outwardlyprojecting lugs or ribs which engage the barrel interior side wallduring activation of the plunger rod axially in the barrel duringfilling of the syringe or activation of the plunger in an injectioncycle. Even though these syringes are generally suitable for thepurposes, it is been found that in some instances they are relativelyexpensive to manufacture by reason of the tolerances required to obtainthe desired seal between the plunger ribs and the barrel and to preventbypass or leakage of the medication during an injection stroke and thedesired easy movement of the plunger when activating the same. It hasbeen found that even where tolerances are controlled, leakage and easeof activation of the plunger are problematic.

REFERENCE PATENTS

[0004] BRAITHWAITE TITLE: SYRINGES U.S. Pat. No. 5,066,280 DATE OFPATENT: NOV. 19, 1991

[0005] LINNEBJERG TITLE: PRELOADABLE SYRINGE FOR AUTOMATED DISPENSINGDEVICE U.S. Pat. No. 5,928,202 DATE OF PATENT: JUL. 27, 1999

[0006] DEDOLA et al. TITLE: SYRINGES AND PLUNGERS FOR USE THEREIN U.S.Pat. No. 6,224,577 DATE OF PATENT: MAY 1, 2001

[0007] STEVENS et al. TITLE: SYRINGE PLUNGER TIP U.S. Pat. No. 5,735,825DATE OF PATENT: APR. 7, 1998

[0008] SOMERS TITLE: SAFETY SYRINGE U.S. Pat. No. 6,342,045 DATE OFPATENT: JAN. 29, 2002

[0009] KOLBERG et al. TITLE: PREFILLED, STERILIZED SYRINGE WITH A NEWAND IMPROVED PLUG U.S. Pat. No. 6,142,977 DATE OF PATENT: NOV. 7, 2000

[0010] DURÄNZAMPA et al. TITLE: AUTO-NON-REUSABLE SYRINGE-NEEDLE SYSTEMFOR INJECTIONS FOR A UNIQUE USE U.S. Pat. No. 5,034,002 DATE OF PATENT:JUL. 23, 1991

[0011] GROSS TITLE: LOW FRICTION SYRINGE U.S. Pat. No. 5,397,313 DATE OFPATENT: MAR. 14, 1995

SUMMARY OF THE INVENTION

[0012] With the foregoing in mind, it is an object of the presentinvention to provide an oral dose dispenser for use in administeringmedicaments, such as liquid aspirin to children which is characterizedby novel features of construction and arrangement providing an effectiveseal between the plunger and the barrel and is easy to activate whenfilling and administering medicaments and which can be manufactured by aunique molding process easily and economically. In the preferredembodiment of the invention, the plunger has a unique and distinctivetip configuration including a circumferentially extending axiallydirected sealing or wiper lip which projects outwardly at apredetermined lead angle of approximately ten degrees (10°) to the axisof hollow tubular plunger in the relaxed state. By this construction,the sealing or wiper lip provide essentially a circumferentiallyextending single point of contact with the barrel bore surface and thus,the present invention combines the advantages of the prior art rubberand plastic plungers since it is economical to manufacture and functionsproperly over a widertolerance range. In other words, the plunger-barreldesign of the present invention has the desired “feel” for ease ofactuation over a wide range of tolerances. The plunger easily rides inthe barrel and ensures a clean and in depth dispensing of the productthrough the discharge tip in the barrel.

[0013] In a preferred embodiment, the plunger and barrel are made ofdissimilar materials to provide greater lubricity between the plungerand the barrel which contributes to easy movement and which preventsgalling. The barrel is preferably made of a clear plastic, such aspolypropylene, and the plunger is made of a high-density polyethyleneand is of an opaque color so that the contrast provided by the sealinglip arrangement and the plunger tip makes it easy for the user todetermine the fill height when filling the dispenser as explained inmore detail hereafter. Typically, these assemblies comprising a rubberplunger and a plastic or glass barrel are not tolerance sensitive sincean external lubricant is usually applied to the plunger to facilitaterelatively easy movement of the plunger in the barrel. With theseplural-part assemblies, however, the plunger can easily disassemble fromthe plunger rod and present a choking hazard to a child. Plasticplungers are also known and are less expensive to manufacture butgenerally present tolerance problems. For example, it has been foundthat small tolerance variations from one assembly to the next can make alarge change in how smoothly the plunger rides in the barrel whenactivated.

[0014] Further as explained, the molding process of the presentinvention is greatly simplified because only mold components which actin two directions are required to form the plunger configuration withthe flexible axially extending sealing lip. The prior art does notdisclose a plunger and barrel combination where the plunger and barrelare essentially elongated, hollow tubular members and the plunger has asealing lip formed integrally therewith providing the only contactelement with the barrel during activation to fill or discharge liquidproducts, such as medicaments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] These and other objects of the present invention and variousfeatures and details of the operation and construction thereof arehereinafter more fully set forth with reference to the accompanyingdrawings wherein;

[0016]FIG. 1 is a perspective view of a plunger and barrel of an oraldispensing assembly in accordance with the present inventionparticularly adapted for administering medicaments to children;

[0017]FIG. 2 is an enlarged fragmentary sectional view taken on lines2-2 of FIG. 1 showing the plunger tip configuration;

[0018]FIG. 3a is a transverse sectional view of the plunger and barrelassembled;

[0019]FIG. 3b is an enlarged sectional view showing the sealing lipengaging the inside of the barrel;

[0020]FIG. 4a is a transverse sectional view similar to FIG. 3a showingthe plunger at the upper end of its retract stroke;

[0021]FIG. 4b is an enlarged fragmentary sectional view of the portioncircled in FIG. 4a and identified by numeral 4 b;

[0022]FIG. 5a is a transverse sectional view showing the plunger fullybottomed out and the contents completely dispensed;

[0023]FIG. 5b is an enlarged fragmentary sectional view of the portioncircled in FIG. 5a identified by the reference numeral 5 b;

[0024]FIG. 6 is an exploded side elevational view of another embodimentof oral dispensing assembly in accordance with the present invention;

[0025]FIG. 7 is an enlarged exploded view of the tip of the plungercircled in FIG. 6 and identified by the reference numeral 7;

[0026]FIG. 8a is a transverse sectional view showing the plungerassembled in the barrel;

[0027]FIG. 8b is an enlarged fragmentary view of the portioned circledin FIG. 8a and referenced by the numeral 8 b;

[0028]FIG. 9a is a transverse sectional view similar to FIG. 8a with theplunger fully withdrawn;

[0029]FIG. 9b is an enlarged view showing the relationship of the partswhen the plunger and barrel are in the position shown in FIG. 9a;

[0030]FIG. 9c is an exploded, enlarged fragmentary sectional view of theplunger tip and entrance end of the barrel;

[0031]FIG. 10a is a transverse sectional view similar to FIGS. 8a and 9a where the plunger is fully bottomed out in the barrel during adischarge stroke;

[0032]FIG. 10b is an enlarged fragmentary sectional view of the portioncircled in FIG. 10a and identified by the reference numeral 10 b;

[0033]FIG. 11 is a transverse, sectional view of a molding apparatus formaking a plunger for the dispenser assembly shown in FIGS. 6-10inclusive;

[0034]FIG. 12 is a transverse, sectional view similar to FIG. 11 showingthe first stage in the plunger part removal process;

[0035]FIG. 13. Is a transverse, sectional view showing the next stage inthe plunger part removal process;

[0036] FIGS. 14-16 inclusive are transverse, sectional views showingsequentially the steps for removing the plunger part;

[0037]FIG. 17 is an enlarged fragmentary, transverse, sectional view ofthe front and rear cavity;

[0038]FIG. 18 is a fragmentary view similar to FIG. 12; and

[0039]FIG. 19 is an enlarged fragmentary, sectional view showing theparts as they are in FIG. 13.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0040] Referring now to the drawings and particularly to FIG. 1 thereof,there is shown an oral dispensing assembly in accordance with thepresent invention generally designated by the numeral (10), as shown theassembly comprises an elongated plunger (12) which fits in and slides inan elongated, hollow barrel (14).

[0041] The barrel (14) as best illustrated in FIGS. 5a and 5 b is madeof a plastic material and comprises a generally cylindrical, elongatedside wall (18) having a bore (18 ^(a)) of generally uniform diameter Dfor its length having a tip (20) at one end with a discharge opening(22) through which medicament products are dispensed. The tip end (20)as illustrated in 5 b is of a greater cross section T than the barrelside wall thickness T−1 to define a circumferentially extending ledge(24). The interior of the tip (20) is shaped to define a spherical seat(26). The barrel (14) is outwardly flared at its opposing upper terminalend as at (30) and has a pair of circumferentially extending spacedprotrusions (34) and (36) in the region where the cylindrical bodyportion (18) of the barrel merge with the outwardly flared finger gripportion (30).

[0042] The plunger (12) is also made of plastic and has an elongatedgenerally cylindrical elongated body portion (40) which is outwardlyflared to define a flange (42) at its upper end serving as a finger gripportion for activation of the plunger in the barrel. The plunger (12) asillustrated has a bulbous nose (44) at its tip end. The nose portion(44) is offset from the side wall (40) as shown at 5 b and has a crosssectional thickness T−2 slightly greater than the cross section T−3 ofcylindrical body portion of the plunger. A downwardly and slightlyoutwardly biased sealing lip (46) projects axially from the lower end ofthe plunger at the juncture (48) of the cylindrical body portion (40)and nose section (44) and has a slightly beveled outer edge (47)confronting the inner wall of the barrel as shown in FIG. 3b. The tip ofthe sealing lip (46) is spaced upwardly from the nose portion so thatwhen the plunger is fully seated the sealing lip (46) engages the ledge(24) when the nose portion engages the spherical seat. The sealing lip(40) projects outwardly at an angle alpha (α) of about ten degrees (10°)to the longitudinal axis A-A of the plunger.

[0043] The inside diameter D of the barrel is slightly greater than theexternal diameter D₂ of the plunger to provide a slight clearance Cbetween the parts so that the flexible sealing lip (46) is essentiallythe sole contact when activating the plunger to fill or dischargeproduct.

[0044] The barrel (14) is preferably made of polypropylene and theplunger (12) is preferably made of a high-density polyethylene. It hasbeen found that this combination of materials and the specificconfiguration facilitate easy sliding of the parts relative to oneanother and does not require the close molding tolerances that prior artsyringes require. Further the plunger (12) is easy and economical tomanufacture by reason of the simple mold design which does not requireside action components. The tooling therefore is relatively simple anddoes not require the complex tooling which prior art syringe assembliesrequire. The tooling can accommodate more cavities for a given tonnageand is therefore very economical and cost saving.

[0045] Consider briefly the use of an oral dosing assembly in accordancewith the present invention. With the plunger (12) fully seated in thebarrel (14) as shown in FIG. 5a, the user simply inserts the barrel andplunger into a container for the medicament to be dispensed the userthen pulls the plunger (12) upwardly to draw the desired quantity intothe barrel. The barrel is graduated in markings to aid in the fillingprocess. The user then simply inserts the tip end into the mouth of achild and pushes the barrel forwardly to dispense product. It is notedthat when the barrel is drawn to its outer-limit position, the sealinglip (40) engages in one of the protrusions signaling the user not towithdraw the plunger any further.

[0046] There is shown in FIGS. 7-10 inclusive another embodiment ofdispenser assembly in accordance with the present invention generallydesignated by the numeral (50) which comprises an elongated, hollowbarrel (52) and a plunger (54) slidably mounted in the barrel (52). Thebarrel (52) as illustrated has an elongated, generally cylindrical bodyportion (56) terminating at its upper end in radially outwardly directedcircumferentially extending flange (58) providing a finger grip for theuser. The tip (59) has a discharge opening (60) and is connected to theside wall (56) by a downwardly flared conical connecting wall (62).

[0047] The plunger (54) has an elongated body portion (54 a) having agenerally uniform diameter (D₄) which has an outwardly flared section(54 ^(b)) at its upper open end and terminates in a circumferentiallyextending radially outwardly directed flange (66) serving as a fingergrip for the user to activate the plunger in the barrel. The tip end(55) of the plunger (54) has an axially extending wall (68) offsetradially to provide a circumferentially extending space or pocket Sbetween the sealing lip (40) and tip (55). The tip (55) is of athickness T−3 greater than the cross sectional wall thickness T−4 of thebody portion of the plunger. A downwardly and inwardly extending bottomwall (70) has raised a central indentation (72). The slanted outer-faceof the bottom wall (70) preferably is disposed at a predetermined anglerelative to a plane P-P through the axis A-A of the plunger so that itseats flush against the interior downwardly tapered face (62) of thebarrel when the plunger is fully seated at the end of a discharge strokeas shown in FIG. 10a. A flexible sealing lip (40) is formed integrallywith the plunger and in the relaxed state projects at an angle alpha (α)of about ten degrees (10°) relative to the axis A-A of the plunger. Thesealing lip (40) has an outer beveled surface (40 ^(a)) which engagesthe inner side wall of the barrel to provide good sliding movement whenactivating the plunger in the barrel. Similar to the previouslydescribed embodiment, the outer barrel is preferably made of propyleneand the plunger is preferably made of a high-density polyethylene sincethe combination of these materials and the specific configuration of thesealing lip facilitates movement of the parts relative to one anotherand does not require the close molding tolerances to provide goodsliding action.

[0048] The slightly outwardly tapered section (52 ^(b)) of the barrelbore (52 ^(c)) at the open end is preferably angularly disposed relativeto the longitudinal axis A-A of the barrel at an angle beta (β) ofbetween three and five degrees (3° and 5°) thereby defining an openingat the top of the barrel of a diameter (D₆) greater than the diameter(D₅) of the flexible lip (40) in the relaxed state to thereby allow easyassembly of the parts without damage to the flexible wiper lip. Theflexible sealing lip (40) engages the rib (53) at the maximum stroke tosignal the user that the parts are in the position shown in FIGS. 9a and9 b. As shown in the drawings, the wiper lip is compressed slightly whenit rides in the main portion of the barrel to provide the desired lightessentially single line contact with the bore of the barrel for ease ofoperation of the dispenser in a manner to provide an effective sealpreventing blow by of the liquid product when activating the plunger todischarge product through the discharge opening.

[0049] It is noted that even know the dispenser assembly of the presentinvention has been shown and described in connection with dispensingmedicaments for children, the dispensing assembly has many other usefulapplications for dispensing other types of liquid products. Further,even though the high-density polyethylene and polypropylene are thepreferred combination of materials, in some applications, otherdissimilar combinations of materials may be used which provide the goodsliding action between the flexible wiper lip or flange and the interiorwall of the barrel.

[0050] There is shown in FIGS. 11-19 inclusive a method and moldingapparatus for manufacturing plungers for the dispenser assembly shown inFIGS. 6-10 inclusive. This method and apparatus are characterized bynovel features of construction and arrangement facilitating easy andeconomical manufacture of plungers. The molding apparatus as shown inFIG. 11 comprises an elongated, tubular one-piece rear cavity (80)having an elongated generally cylindrical mold cavity (82) which isflared outwardly as to (83) adjacent one end to form the tapered boresection T of the plunger 54. The opposite end is also slightly taperedoutwardly as at (85) to facilitate formation of the axially directedwiper lip (40). The molding apparatus also includes a front cavity (88)comprising a gate bushing (90) and a manifold probe (92). The gatebushing (90) is formed with a tapered front wall (94) which abuts acomplementary tapered wall (87) on the front end of the rear cavity whenthe mold is closed. The gate bushing (90) has a circumferentiallyextending axially directed rim (94) which forms the circumferentiallyextending space or gap S between the wiper lip (40) and the tip portion(70) of the plunger (54) which permits the wiper lip (40) to bedeflected radially inwardly when the finished plunger is withdrawn fromthe rear cavity as shown in FIG. 13. In otherwords, the diameter D₅ ofthe tip portion (70) of the plunger (54) and the cross-sectionalthickness T_(w) of the wiper lip (40) are slightly less than the outerdiameter to of the plunger to allow radially inward deflection of thewiper lip (40) when the core (95) is withdrawn in the manner shown inFIG. 13. The core (95) mounts an injector collar (93) which whenactuated forwardly engages the radial flange at the outer end of theplunger (54) to strip it from the core (95) in the manner shown in FIG.15 and FIG. 16.

[0051] Consider the operation of the molding apparatus and systemdescribed. With the mold parts in relative positions shown in FIG. 11,the gate (90 a) is opened to allow the plastic material to form the partin the manner shown in FIG. 11. The gate bushing (90) is then withdrawnto the position shown in FIG. 12. When the mold is opened in thisfashion to break the gate, it provides the necessary clearance to allowthe flexible wiper lip (40) to collapse and be withdrawn from the moldcavity. The mold starts to open at the next position (FIG. 13) allowingthe plunger part (54) to start withdrawing from the cavity while theflexible wiper lip (40) collapses radially inwardly. The mold continuesto open in the manner shown in FIG. 14 allowing the plunger part tocompletely withdraw from the cavity while the flexible wiper lip (40)expands to its normal position and provide enough clearance to eject theplunger part (See FIG. 16). The ejector plate is activated forwardlystripping the plunger part from the core at the end of the stroke theplunger part is released from the mold (See FIG. 16).

[0052] Even though particular embodiments of the present invention havebeen illustrated and described herein, it is not intended to limit theinvention and changes and modifications may be made therein within thescope of the following claims.

What is claimed is:
 1. A dispenser assembly for liquid productscomprising an elongated, generally cylindrical barrel of a predeterminedinternal cross-sectional diameter having a discharge opening at one endand open at its opposite end, an elongated, generally cylindrical hollowplunger having an outer diameter less than the barrel internal diameterand a circumferentially extending axially directed sealing lip adjacentthe tip portion having an outer diameter greater than the internaldiameter of the barrel in the relaxed state to thereby flex the lipinwardly against its bias and providing the sole sliding contact betweenthe plunger and barrel when the plunger and barrel are actuated axiallyrelative to one another.
 2. A dispenser assembly as claimed in claim 1wherein the outer peripheral edge of the flexible lip is chamfered tofacilitate ease of assembly to the barrel and provide a single linecontact with the bore of the barrel.
 3. A dispenser assembly as claim inclaim 1 wherein the bore of the body portion of the barrel is of apredetermined generally uniform diameter and is flared outwardlyadjacent the open end and has a maximum diameter slightly greater thanthe maximum diameter of the flexible lip in the relaxed state tofacilitate easy assembly.
 4. A dispenser assembly as claimed in claim 3,including a radially inwardly directed bead at the juncture of the boreof the body portion and tapered section which determines the upper limitposition of the plunger.
 5. A dispenser assembly as claim in claim 1wherein the barrel and plunger are made of dissimilar materials toprovide a degree of lubricity distributing to ease of movement of theplunger in the bore of the barrel.
 6. A molding apparatus for making anelongated hollow, tubular plunger part having a tip portion and anaxially directed flexible wiper lip extending forwardly to overlap aportion of the tip at a predetermined angle comprising an elongatedone-piece rear cavity having a generally cylindrical bore extendingaxially the length of the cavity, said bore tapering downwardly andoutwardly at one end, a front cavity having a circumferentiallyextending axially projecting rim at one end engageable in the moldcavity and spaced therefrom to form the flexible wiper lip spaced fromthe tip portion so that when the core is activated axially to withdrawthe plunger part, the lip is compressed radially inwardly to a pointwhere it freely slides in the mold cavity to permit the finished plungerart to be withdrawn axially.
 7. Apparatus for making a plunger partcomprising an elongated, hollow generally cylindrical body having a tipportion at one end and a flexible, axially, extending wiper lip, saidapparatus comprising an elongated cavity and a core engageable in thecavity bore and constructed and operated in a manner such that when thecore is activated axially in the bore, the lip is compressed radiallyinwardly to a point where it freely slides in the mold cavity to permitthe plunger part to be withdrawn axially.
 8. A method for molding aplunger part having an elongated generally tubular body portion, a tipportion at one end and a flexible, axially extending lipcircumferentially overlying the tip portion consisting of the steps of:a.) molding the plunger part in a hollow mold cavity and a core; and b.)axially actuating the core and mold cavity whereby the lip is compressedradially inwardly to a point where it freely slides in the mold cavityto permit the plunger part to be withdrawn axially.